Whether a movie is in PAL or NTSC doesn't really matter unless you burn it as a DVD. I think that most converters have the options to change this. The players that you use on your computer will get info on the framerate from the file and play it accordingly.

You can see whether a video is PAL or NTSC by using G-Spot to check the file

http://www.headbands.com/gspot/

It will not say if it PAL or NTSC but you will see framarate

PAL being between 23.68 and 25 (usually 23.68)

NTSC being closer to 30 (usually 29.96 if I remember correctly)